Why do none of the links that I put in my outgoing yahoo emails no longer underline themselves and become live when I finish typing them and hit the space bar?

Previously, when I typed my email address in an outgoing email or cut and pasted a link from my browser bar the link would become 'live' when I hit the space bar or 'enter' key. The link would turn blue and underline itself and the person receiving the email could just click on that live link and be taken to the site. Now the link does not turn blue or underline itself and the receiver must cut and paste the link into their browser bar to use it.

Why? I did not change anything in Yahoo or Mozilla.

I have deleted and reinstalled Java to no effect. I am using html in Yahoo.

Previously, when I typed my email address in an outgoing email or cut and pasted a link from my browser bar the link would become 'live' when I hit the space bar or 'enter' key. The link would turn blue and underline itself and the person receiving the email could just click on that live link and be taken to the site. Now the link does not turn blue or underline itself and the receiver must cut and paste the link into their browser bar to use it.
Why? I did not change anything in Yahoo or Mozilla.
I have deleted and reinstalled Java to no effect. I am using html in Yahoo.